Physiology of Flight
What are the decompression sickness symptoms?
- Joint pain
- Chest Pain
- Visual and Mental Impairment
- Pins and needles
Bad cases may collapse
What is decompression sickness?
Build up of nitrogen bubbles in the blood caused by either scuba diving for cabin decompression
What is atmospheric pressure?
Combined weight of atmospheric gases- nitrogen and oxygen creating a downward force.
It varies according tothe height above sea level
What are the symptoms of hypoxia?
- Breathlessness
- Headaches
- Increased pulse rate
- Unwarrented self confidence
- Sleepiness
- Lack of concentration
What are contributing causes of Hypoxia?
- Heart conditions
- Respiratory illness
- Blood disorders
- Heavy smoking
- Drug and alcohol users
What is the atmosphere made up of?
Nitrogen and Oxygen- and a small amount of of other gases
What decreases as altitude increases?
Temperature- approximately 2 degrees per 1000ft.
What is an explosive decompression?
When air escapes in a rush. Can be heard as an explosive noise, eg: loss of a cargo door.
What is a sudden decompression?
Total dailure of pressurisation system. Fuselage stays in tact.
What is a gradual decompression?
Partial failure of pressurisation equipment of slow pressurisation leak. Fuselage will stay in tact and it may go unnoticed until cabin reaches 1400ft and warning goes off.
What is the cabin altitude maintained around?
5000ft
What position should conscious and unconcious people recieve oxygen in?
Conscious- administer while sitting up right
Unconscious- administer whilst in recovering position
What can you do to help decompression sickness?
Administer oxygen, seek immediate medical assistance and if cleared emergency, inform captain and they will lower aircraft to lower altitude and land ASAP
What is hypoxia?
Hyp- low or reduced
oxia- oxygen
Lack of oxygen
What happends if decompression occurs?
The cabin pressure matches the outside pressure. Warnings will occur when the cabin altitude reaches 14,000ft and above and oxygen is advised.
Between how many ft does your body still function?
Sea level to 10,000ft.
What treatment can you do to help gas expansion?
- Swallowing
- Yawning
- Sucking on a sweet
- Blowing nose
- Holding nose and gently exhaling
- Passing wind/belching
How is hypoxia treated?
Administering oxygen until condition is relieved.
What areas of the body does gas expansion effect?
- Ears
- Sinuses
- Abdomen
- Teeth
What is gas expansion?
When gases in your body become trapped and cause pressure due to parts of the body being unable to expand. It can lead to severe pain.
What does atmosphere provide us on earth?
Oxygen, carbon dioxide and rain
What happens to atmospheric pressure when altitude increases?
Atmospheric pressure decreases. Gas expands at higher altitude, meaning particles are able to spread further apart.
How is the aircraft pressurised?
- Air from the engines is pumped through the air conditioning pack and up into the cabin.
- Varying the amount of air allowed to escape through adjustable outflow valves, controls the cabin pressure.
What is most likely happening if our respiration rate increases?
Altitude increasing= breathing deeper and faster
What are the visible signs of hypoxia?
Blueness in fingertips and lips
Laboured breathing
What are the effects on crew or passengers due to decompression?
- A need to breath rapidly
- Discomfort of pain due to pressure of gasses trapped
- Initial effects of hypoxia
What does time of useless consciousness mean?
Amount of time since sudden lack of oxygen and the start of physical or mental impairment, preventing you from taking rational action. Eg. putting on oxygen mask.